Transmission line pulse (TLP) testing methods have been developed to test circuitry using simulated electrostatic discharge (ESD) pulses under the charged device model (CDM). Thus, high current pulses may be generated by charging a transmission line, and subsequently taking advantage of the impedance and high breakdown voltage of the line to generate a relatively high voltage discharge pulse for a short time. A polarized matching load or an attenuator may be used to terminate the line, and a directional coupler may be used to transport the pulse to the device under test.
When especially short pulses are anticipated (e.g., less than about 5 nanoseconds), it may be useful to select an attenuator rated at about −6 db to −10 db so that echo pulses returned to the testing apparatus from an unmatched device under test, as well as the open end of the charged line, are significantly reduced (e.g., by about 12 to 20 db, respectively) from the amplitude of the discharge pulse. However, using an attenuator in this fashion may also reduce the magnitude of the discharge pulse itself, perhaps to such an extent that the value of the test is compromised.